Field of the Invention
The present invention relates to a photoelectric conversion device and a method of driving a photoelectric conversion device.
Description of the Related Art
As a color document reading unit of a document reading apparatus, such as a copying machine or a multi-function printer, there is known a color document reading unit using a photoelectric conversion device, such as a complementary metal oxide semiconductor (CMOS) image sensor or a charge coupled device (CCD) image sensor. In each of Japanese Patent Application Laid-Open Nos. S62-49765, H08-116402, and H02-250560, there is disclosed a photoelectric conversion device, which is configured to separate colors of a color document by red (R), green (G), and blue (B) optical filters to acquire image information.
In the photoelectric conversion device disclosed in Japanese Patent Application Laid-Open Nos. S62-49765, H08-116402, and H02-250560, pixels in a plurality of columns are arranged in a main scanning direction, and an R-pixel, a G-pixel, and a B-pixel are arranged periodically. Pixels in three rows are arranged in a sub-scanning direction, and the R-pixel, the G-pixel, and the B-pixel are arranged periodically.
In the photoelectric conversion device disclosed in Japanese Patent Application Laid-Open Nos. S62-49765, H08-116402, and H02-250560, when signals of pixels are read out in order along the main scanning direction, signals of the R-pixel, the G-pixel, and the B-pixel are read out in order. Potentials of the signals of the R-pixel, the G-pixel, and the B-pixel are often different from one another depending on the color document to be read. For example, assuming a case where the potential of the signal of the R-pixel is high, and the potential of the signal of the G-pixel is low, the signal of the G-pixel having the low potential, which is read out after the signal of the R-pixel having the high potential is read out, may have a potential that is higher than a true value. In this manner, when the signals of the R-pixel, the G-pixel, and the B-pixel are read out in order, so-called electric color mixing of the pixel signals has occurred in some cases under the effect of the signal of the previously-read pixel of a different color. When the electric color mixing occurs, color reproducibility may be reduced when the captured image is reproduced.